Occupational Dairy Exposure and IgE-mediated Allergic Disease in Yakima, WA

Abstract

Background: Many studies have linked childhood farm exposures to a protective effect against allergy and asthma. Although continued exposure in adulthood may maintain this effect, little work has been done looking specifically at adult occupational exposures. This study focuses on dairy farming exposures in the Yakima Valley in Washington state, a region whose trends toward intensification of dairy farming and shifts to a primarily Latino work force represent the recent changes in the larger U.S. industry. Objective: The objective of this study is to evaluate the prevalence of allergic sensitization in dairy farm workers as compared to community controls. Methods: Total and cow epithelium specific IgE levels were measured from the serum of 41 dairy farm workers and 36 community controls. Relevant information regarding occupation, demographics, and allergy symptoms was obtained via a questionnaire. Linear regression methods were used to compare IgE levels between exposure groups and adjust for potential confounders. Additionally, the relationship between IgE levels and exhaled nitric oxide (eNO) was evaluated using linear regression and counts for allergy symptoms and asthma diagnosis were evaluated with Fisher’s Exact Test. Results: There was no significant evidence for the association between dairy farm exposure and total IgE, but sensitization to bovine allergen was higher in dairy workers as compared to controls. Additionally, sensitization to bovine allergen was associated with higher levels of eNO. Conclusion: No evidence for a protective effect of farm exposure on total IgE was found, but dairy workers may be at higher risk for sensitization to bovine aeroallergens and subsequent airway inflammation.